The present invention relates to an apparatus for the manufacture of rock bolts.
In Australian Patent Number 640906 there is described and claimed an apparatus for the manufacture of a multi-strand rock bolt which is formed with bulbs or expanded portions in which a king wire is disposed at the periphery of the bulb.
The present invention provides an apparatus which is for the manufacture of multi-strand rock bolts formed with bulbs in which the feed material is fed from a rotatable reel.
In accordance with one aspect of the present invention there is provided an apparatus for manufacturing multi-strand rock bolts having spaced apart bulbs formed therein, characterised by a feed means for supplying a multi-strand cable from a rotatable supply reel, a means for forming the cable with bulbs at spaced intervals and a means for determining the position of the cable to stop operation of the feed means to enable a further bulb to be formed.
Preferably, means is provided for sensing the position of an already formed bulb to stop operation of the feed means. The means for sensing the position of a formed bulb may comprise a sensor means having means which are moved away from the cable by the formed bulb so as to cause a signal to be sent to the feed means to stop operation thereof.
Further, a brake is preferably provided to hold the multi strand cable in a desired position when the feed means is stopped.
The feed means preferably has a plurality of rollers which clamp the multi strand cable to cause it to be fed from the supply reel. One of the rollers of the feed means may be rotably driven by a drive means.
Further, the apparatus typically has means for forming a bulb in the form of pairs of opposed jaws which are initially spaced apart by a first distance, the jaws of each pair being are arranged to be brought together to clamp the multi strand cable and the pairs of jaws being subsequently arranged to be moved closer together to be spaced apart by a second smaller distance so as to form a bulb in the multi strand cable, and the pairs of jaws being arranged to subsequently release the multi strand cable and to be moved back to the position in which they are spaced apart by the first distance.
Means may be provided for collecting the multi strand cable formed with bulbs at spaced intervals on a take up reel. In this connection there may be provided an axially rotatable bail arm having a bail member which guides the multi strand cable onto the take up reel. The bail arm may have axially rotatable threaded shaft having the bail member threadedly engaged therewith so that the bail member can travel along the shaft as the latter rotates.
In accordance with a further aspect of the present invention there is provided a method of manufacturing a multi strand rock bolt having spaced apart bulbs formed therein characterised by feeding a multi strand cable from a rotatable supply reel, sensing when the cable has reached a certain position and stopping movement of the cable, forming a bulb in the stopped cable, recommencing movement of the cable and repeating the sequence.